Mark-
Your plans sound pretty solid. Just a couple of comments. First, 330w
sounds like a good amount for the substrate heater. I'd back it up with a
150-250w Ebo-Jaeger in the sump, set 3 degrees cooler than the controller
for the cables. That way, if your house gets (for some random reason) cold
for a significant period of time and overwhelms the cables' ability to heat
you have a backup that can kick in and keep the tank from getting too cold.
As for the laterite, I don't know anything about the first layer stuff,
and I suspect it is too new for anyone to have any kind of good long term
data. I'd look into Carl Schuller's (speling?) Substrate Gold, which has
been around forever and has been used with success by many of the people on
this list.
Your lighting plans sounds good, but are maybe a bit high. I'd be
tempted to just use the 3 MH. For some reason (surface area I suspect),
larger tanks need less light. At www.thekrib.com there is a great
discussion on the use of watts per square meter rather than watts/gallon,
which explains some of this. I'm using 280w on a 100 gallon, and can grow
pretty much anything I want, with reduced risk of chronic algae problems.
The more light you put in, the more carefully balanced you have to have the
nutrients.
I feel that wet/dry filtration is the best choice for a larger tank, as
the loss of CO2 is minimal if you keep it well-sealed, and the oxygenation
is a fine thing. It also is probably the most efficient form of filtration
available. Building one is easy (took me about 10 hours or so), and cheap.
I've heard that the A-B CO2 reactor is junk, and I'd be suprised, even if it
was any good, if it would work on a tank as large as the one you're
planning. I'd build your own, or I'll sell you one I built (not pretty, but
they work well) for a little more than the cost of materials. I suspect
pretty much any bubble counter will work. I use the Dupla unit, but only
because I got it on sale from Burleson when they quit carrying Dupla.
Hope this helps, and feel free to email me with any questions.
Justin Collins
in (FINALLY!) sunny Bellingham, WA.